Sulfated Benzimidazolone Derivatives Having Mixed Serotonine Receptor Affinity

ABSTRACT

The present invention pertains to a compound of formula (I) 
     
       
         
         
             
             
         
       
     
     wherein R 1 , R 2 , R 3 , and R 4  are each hydrogen or sulfate monoester with the proviso that R 1 , R 2 , R 3 , and R 4  cannot simultaneously be hydrogen, processes for their preparation and their use as pharmaceuticals in the treatment of CNS disorders.

The present invention relates to novel pharmacologically activebenzimidazolone derivatives and their addiction salts which bind theserotonine and dopamine receptors, to their preparation and their usefor therapeutic purposes. These compounds, owing to theirpharmacological activity, are useful in the treatment of CNS disorders.

BACKGROUND OF THE INVENTION

Serotonine (5-HT) recognises several well defined cell surfacereceptors. Among these, 5-HT_(1A) and 5-HT_(2A) at which serotonine havehigh affinity, are known to be implicated in many Central Nervous Systemdisorders such as sexual disorders, depression, anxiety, schizophrenia,Parkinson and neurodegenerative diseases (EP 0 526 434 B1; WO 01/21593A1; WO 02/24661 A2; WO 02/24662 A1; WO 03/014079 A1; WO 03/013539 A1; WO03/035072 A1; WO 05/102343 A1; WO 06/019715 A1; WO 06/010574 A1; WO06/024471 A1.

In the previous art, several classes of compounds able to interfere withthe neurotransmission at serotonine or dopamine receptor subtypes areknown. Particularly, derivatives based on the core structure of thearylpiperazine and benzimidazolone have been described (e.g. GB 2023594,U.S. Pat. No. 3,472,854, U.S. Pat. No. 4,954,503 and WO 98/33784), andtargeted both to generic serotonine or dopamine receptors and to aspecific receptor subtype. In another patent (U.S. Pat. No. 5,576,318)compounds based both on the benzimidazolone and phenyl piperazinestructures are described: in this latter case the described affinitiesare limited to 5-HT_(1A) and 5-HT_(2A) receptor subtypes. Furthercompounds with affinity to 5-HT receptors and their synthesis have beendisclosed in WO 01/21593 A1.

DETAILED DESCRIPTION OF THE INVENTION

Here we describe, and this is one object of the present invention, newsulfate esters based on the benzimidazolone phenyl piperazine structure.Surprisingly it was discovered that the compounds according to thisinvention possess an interesting affinity profile at the said serotoninereceptor subtypes: indeed, some of them have a high and preferentialaffinity at a given site (e.g. 5-HT_(1A) or 5-HT_(2A)).

Owing to their peculiar profile, the present compounds may play a rolein the regulation of neurotransmission at the serotonine sites and thusmay be of value in the treatment of those diseases where an alteredfunctioning of neurosignal transmission is present. Examples of theseCNS disorders include depression, schizophrenia, Parkinson, anxiety,sleep disturbances, sexual and mental disorders and age associatedmemory impairment.

According to the present invention, we provide compounds of generalformula (I)

whereinR₁, R₂, R₃, and R₄ denote hydrogen or sulfate monoester with the provisothat R₁, R₂, R₃, and R₄ cannot simultaneously represent hydrogen.

Preferred compounds according to the invention are those of generalformula (I) wherein two or three of the four radicals R₁, R₂, R₃, and R₄denote hydrogen.

Also preferred are compounds of general formula (I) wherein one of theradicals R₁, R₂, R₃, and R₄ denotes sulfate, whilst the other radicalsrepresent hydrogen.

Of particular interest are compounds selected from the group consistingof:

It is understood that the compounds represented by formula (I) may existalso as the corresponding zwitter ion form and that while both forms areincluded within the meaning of the structural formula, for simplicitysake, only the free acid form is shown.

For the pharmaceutical use the compounds of general formula (I) may beused also in the form of pharmacologically acceptable salts. As usedherein, “acceptable salts” refer to derivatives of the disclosedcompounds wherein the parent compound is modified by making acid or basesalts thereof. Examples of pharmaceutically acceptable salts include,but are not limited to, mineral or organic acid salts of basic residuessuch as amines; alkali or organic base salts of acidic residues such assulfuric acid monoesters and the like. The pharmaceutically acceptablesalts include the conventional non-toxic salts or the quaternaryammonium salts of the parent compound formed, for example, fromnon-toxic inorganic or organic acids. For example, such conventionalnon-toxic salts include those derived from inorganic acids such ashydrochloric, hydrobromic, sulfuric, sulfamic, phosphoric, nitric andthe like; and the salts prepared from organic acids such as acetic,gluconic, isethionic, glycinic, mucoic, propionic, succinic, glycolic,stearic, lactic, malic, tartaric, citric, ascorbic, pamoic, maleic,hydroxymaleic, phenylacetic, glutamic, benzoic, salicylic, sulfanilic,2-acetoxybenzoic, fumaric, toluenesulfonic, methanesulfonic, ethanedisulfonic, oxalic, isothionic, and the like. Suitable base salts areformed from bases which form non-toxic salts and examples are thelithium, sodium, potassium, aluminium, calcium, magnesium, zinc,ethylamine, diethylamine, ethylenediamine, ethanolamine, diethanolamine,piperazine, choline, arginine, glycine, procaine, tromethamine,benzathine, lysine and meglumine salts (also see Pharmaceutical salts,Berge, S. M. et al., J. Pharm. Sci., (1977), 66, 1-19).

The pharmacologically acceptable salts of the present invention can besynthesized from the parent compound which contains a basic or acidicmoiety by conventional chemical methods. Generally, such salts can beprepared by reacting the free acid or base forms of these compounds witha stoichiometric amount of the appropriate base or acid in water or inan organic solvent, or in a mixture of the two; generally, non-aqueousmedia like ether, ethyl acetate, ethanol, isopropanol, or acetonitrileare preferred.

The phrase “pharmacologically acceptable” is employed herein to refer tothose compounds, materials, compositions, and/or dosage forms which are,within the scope of sound medical judgment, suitable for use in contactwith the tissues of human beings and animals without excessive toxicity,irritation, allergic response, or other problem or complication,commensurate with a reasonable benefit/risk ratio.

In the light of the pharmaceutical efficacy of the compounds of formula(I), the present invention furthermore relates to the use of thosecompounds as a medicament.

A further aspect of the present invention relates to the use ofcompounds of formula (I), optionally in form of the pharmacologicallyacceptable salts thereof for preparing a pharmaceutical composition fortreating diseases in which the use of compounds displaying affinity forthe 5-HT_(1A) and 5-HT₂-receptor may have a therapeutic benefit.

In a preferred embodiment, the present invention relates to the use ofthe one or more compounds of formula (I) selected from the groupconsisting of compound (I.a), (I.b), (I.c), (I.d), (I.e), (I.f), (I.g),(I.h), (I.i), (I.j), (I.k) and (I.l), most preferably the use of thecompound of formula (I.b), optionally in form of the pharmacologicallyacceptable salts thereof for the preparation of a medicament fortreating diseases in which the use of compounds displaying affinity forthe 5-HT_(1A) and 5-HT₂-receptor may have a therapeutic benefit.

In a further embodiment the present invention relates to the use of oneor more of the compounds of formula (I), more preferably to the use ofone or more compounds of formula (I.a), (I.b), (I.c), (I.d), (I.e),(I.f), (I.g), (I.h), (I.i), (I.j), (I.k) and (I.l), most preferably theuse of the compound of formula (I.b), optionally in form of thepharmacologically acceptable salts thereof for the preparation of amedicament for the treatment of sexual disorders.

The generic term “Sexual disorders” includes Sexual Desire Disorders(i.e. Hypoactive Sexual Desire Disorder, Sexual Aversion Disorder),Sexual Arousal Disorders (i.e. Female Sexual Arousal Disorder, MaleErectile Disorder), Orgasmic Disorders (i.e. Female Orgasmic Disorder,Male Orgasmic Disorder, Premature Ejaculation) Sexual Pain Disorders(i.e. Dyspareunia, Vaginismus), Sexual Dysfunction due to a GeneralMedical Condition, Substance-Induced Sexual Dysfunction, and SexualDysfunction not otherwise specified (Diagnostic and Statistical Manualof Mental Disorders, 4th edition, Text Revision. Washington D.C.,American Psychiatric Association, 2000).

In a preferred embodiment, the present invention relates to the use ofone or more of the compounds of formula (I), more preferably to the useof one or more compounds of formula (I.a), (I.b), (I.c), (I.d), (I.e),(I.f), (I.g), (I.h), (I.i), (I.j), (I.k) and (I.l), most preferably theuse of the compound of formula (I.b), optionally in form of thepharmacologically acceptable salts thereof for the preparation of amedicament for the treatment of sexual desire disorders which are asubgroup of sexual disorders.

In another preferred embodiment the invention relates to the use of oneor more of the compounds of formula (I), more preferably to the use ofone or more compounds of formula (I.a), (I.b), (I.c), (I.d), (I.e),(I.f), (I.g), (I.h), (I.i), (I.j), (I.k) and (I.l), most preferably theuse of the compound of formula (I.b), optionally in form of thepharmacologically acceptable salts thereof for the preparation of amedicament for the treatment of disorders selected from the groupconsisting of hypoactive sexual desire disorder (HSDD), sexual aversiondisorder, loss of sexual desire, lack of sexual desire, decreased sexualdesire, inhibited sexual desire, loss of libido, libido disturbance, andfrigidity.

Further preferred according to the invention is the use of one or moreof the compounds of formula (I), more preferably the use of one or morecompounds of formula (I.a), (I.b), (I.c), (I.d), (I.e), (I.f), (I.g),(I.h), (I.i), (I.j), (I.k) and (I.l), most preferably the use of thecompound of formula (I.b), optionally in form of the pharmacologicallyacceptable salts thereof for the preparation of a medicament for thetreatment of disorders selected from the group consisting of hypoactivesexual desire disorder (HSDD), sexual aversion disorder, loss of sexualdesire, lack of sexual desire, decreased sexual desire, inhibited sexualdesire.

In a more preferred embodiment the invention relates to the use of oneor more of the compounds of formula (I), more preferably to the use ofone or more compounds of formula (I.a), (I.b), (I.c), (I.d), (I.e),(I.f), (I.g), (I.h), (I.i), (I.j), (I.k) and (I.l), most preferably theuse of the compound of formula (I.b), optionally in form of thepharmacologically acceptable salts thereof for the preparation of amedicament for the treatment of disorders selected from the group ofhypoactive sexual desire disorder (HSDD), decreased sexual desire andinhibited sexual desire.

The observed effects of the compounds of formula (I) and the compounds(I.a), (I.b), (I.c), (I.d), (I.e), (I.f), (I.g) and (I.h), (I.i), (I.j),(I.k) and (I.l), most preferably the use of the compound of formula(I.b), optionally in form of the pharmacologically acceptable saltsthereof can be achieved in men and women. However, according to afurther aspect of the invention the use of the compounds of formula (I)and the compounds (I.a), (I.b), (I.c), (I.d), (I.e), (I.f), (I.g) and(I.h), (I.i), (I.j), (I.k) and (I.l), most preferably the use of thecompound of formula (I.b), optionally in form of the pharmacologicallyacceptable salts for the preparation of a medicament for the treatmentof female sexual desire disorders is preferred.

Another object of the present invention is the use of one or more of thecompounds of formula (I), more preferably the use of one or morecompounds of formula (I.a), (I.b), (I.c), (I.d), (I.e), (I.f), (I.g),(I.h), (I.i), (I.j), (I.k) and (I.l), most preferably the use of thecompound of formula (I.b), optionally in form of the pharmacologicallyacceptable salts thereof for the preparation of a medicament for thetreatment of premenstrual disorders.

Further preferred according to the invention is the use of one or moreof the compounds of formula (I), more preferably the use of one or morecompounds of formula (I.a), (I.b), (I.c), (I.d), (I.e), (I.f), (I.g),(I.h), (I.i), (I.j), (I.k) and (I.l), most preferably the use of thecompound of formula (I.b), optionally in form of the pharmacologicallyacceptable salts thereof for the preparation of a medicament for thetreatment of premenstrual disorders selected from the group consistingof premenstrual dysphoria, premenstrual syndrome, premenstrual dysphoricdisorder.

Further preferred according to the invention is the use of one or moreof the compounds of formula (I), more preferably the use of one or morecompounds of formula (I.a), (I.b), (I.c), (I.d), (I.e), (I.f), (I.g),(I.h), (I.i), (I.j), (I.k) and (I.l), most preferably the use of thecompound of formula (I.b), optionally in form of the pharmacologicallyacceptable salts thereof for the preparation of a medicament for thetreatment of sexual arousal disorder in females.

Further preferred according to the invention is the use of one or moreof the compounds of formula (I), more preferably the use of one or morecompounds of formula (I.a), (I.b), (I.c), (I.d), (I.e), (I.f), (I.g),(I.h), (I.i), (I.j), (I.k) and (I.l), most preferably the use of thecompound of formula (I.b), optionally in form of the pharmacologicallyacceptable salts thereof for the preparation of a medicament for thetreatment of male erectile disorder.

Further preferred according to the invention is the use of one or moreof the compounds of formula (I), more preferably the use of one or morecompounds of formula (I.a), (I.b), (I.c), (I.d), (I.e), (I.f), (I.g),(I.h), (I.i), (I.j), (I.k) and (I.l), most preferably the use of thecompound of formula (I.b), optionally in form of the pharmacologicallyacceptable salts thereof for the preparation of a medicament for thetreatment of orgasmic disorder in females.

Further preferred according to the invention is the use of one or moreof the compounds of formula (I), more preferably the use of one or morecompounds of formula (I.a), (I.b), (I.c), (I.d), (I.e), (I.f), (I.g),(I.h), (I.i), (I.j), (I.k) and (I.l), most preferably the use of thecompound of formula (I.b), optionally in form of the pharmacologicallyacceptable salts thereof for the preparation of a medicament for thetreatment of orgasmic disorder in males.

Further preferred according to the invention is the use of one or moreof the compounds of formula (I), more preferably the use of one or morecompounds of formula (I.a), (I.b), (I.c), (I.d), (I.e), (I.f), (I.g),(I.h), (I.i), (I.j), (I.k) and (I.l), most preferably the use of thecompound of formula (I.b), optionally in form of the pharmacologicallyacceptable salts thereof for the preparation of a medicament for thetreatment of premature ejaculation in males.

Further preferred according to the invention is the use of one or moreof the compounds of formula (I), more preferably the use of one or morecompounds of formula (I.a), (I.b), (I.c), (I.d), (I.e), (I.f), (I.g),(I.h), (I.i), (I.j), (I.k) and (I.l), most preferably the use of thecompound of formula (I.b), most preferably the use of the compound offormula (I.b), optionally in form of the pharmacologically acceptablesalts thereof for the preparation of a medicament for the treatment ofsexual pain disorders in females and males.

Further preferred according to the invention is the use of one or moreof the compounds of formula (I), more preferably the use of one or morecompounds of formula (I.a), (I.b), (I.c), (I.d), (I.e), (I.f), (I.g),(I.h), (I.i), (I.j), (I.k) and (I.l), most preferably the use of thecompound of formula (I.b), optionally in form of the pharmacologicallyacceptable salts thereof for the preparation of a medicament for thetreatment sexual pain disorders selected from the group consisting ofdyspareunia in females and males, vaginismus in females, and noncoitalsexual pain disorder in females and males.

Further preferred according to the invention is the use of one or moreof the compounds of formula (I), more preferably the use of one or morecompounds of formula (I.a), (I.b), (I.c), (I.d), (I.e), (I.f), (I.g),(I.h), (I.i), (I.j), (I.k) and (I.l), most preferably the use of thecompound of formula (I.b), optionally in form of the pharmacologicallyacceptable salts thereof for the preparation of a medicament for thetreatment of, sexual dysfunction due to a general medical condition infemales and males.

Further preferred according to the invention is the use of one or moreof the compounds of formula (I), more preferably the use of one or morecompounds of formula (I.a), (I.b), (I.c), (I.d), (I.e), (I.f), (I.g),(I.h), (I.i), (I.j), (I.k) and (I.l), most preferably the use of thecompound of formula (I.b), optionally in form of the pharmacologicallyacceptable salts thereof for the preparation of a medicament for thetreatment of substance-induced sexual dysfunction in females and males.

The beneficial effects of the compounds of formula (I) can be observedregardless of whether the above mentioned sexual disorders existedlifelong or was acquired, is of the “generalized type” or “situationaltype” and independent of etiologic origin (organic—both, physically anddrug induced—, psychogen (due to psychological factors), a combinationof organic—both, physically and drug induced—, and psychogen (due tocombined factors), or unknown) origin. The term “lifelong” refers tosuch sexual disorders of the present invention, which have been presentsince the onset of sexual functioning. The term “acquired” refers tosuch sexual disorders of the present invention which developed onlyafter a period of normal sexual functioning. The “generalized type”refers to such sexual disorders of the present invention wherein thedisorder is not limited to certain types of stimulation, situations, orpartners. The “situational type” applies to such sexual disorders of thepresent invention wherein the disorder is limited to certain types ofstimulation, situations, or partners. The subtype due to “psychologicalfactors” applies when psychological factors are judged to have the majorrole in the onset, severity, exacerbation, or maintenance of the SexualDisorder, and general medical conditions and substance play no role inthe etiology of the sexual disorder. Finally the subtype due to“combined factors” applies when 1) psychological factors are judged tohave a role in the onset, severity, exacerbation, or maintenance of thesexual disorder, and 2) a general medical condition or substance use isalso judged to be contributory but is not sufficient to account for aSexual Disorder (Diagnostic and Statistical Manual of Mental Disorders,4th edition, Text Revision. Washington D.C., American PsychiatricAssociation, 2000).

The beneficial effects of the compounds of formula (I) can also beobserved regardless of whether the females suffering from abovementioned diseases are in the pre-menopausal, peri-menopausal orpost-menopausal state.

As a further feature of the present invention there are providedpharmaceutical compositions comprising as an active ingredient at leastone compound of formula (I), as before defined, or a pharmacologicallyacceptable salt thereof in addition with one or more pharmaceuticalcarrier, diluents or excipients. For pharmaceutical administration thecompounds of general formula (I) and their physiologically acceptablesalts may be incorporated into the conventional pharmaceuticalpreparation in solid, liquid or spray form. The composition may, forexample, be presented in a form suitable for oral, rectal, parenteraladministration or for nasal inhalation: preferred forms include forexample, capsules, tablets, coated tablets, ampoules, suppositories andnasal spray.

The compounds of formula (I), optionally used in form of thepharmacologically acceptable salts thereof, may be incorporated into theconventional pharmaceutical preparation in solid, liquid or spray form.The composition may, for example, be presented in a form suitable fororal, rectal, parenteral administration or for nasal inhalation:preferred forms includes for example, capsules, tablets, coated tablets,ampoules, suppositories and nasal spray.

The active ingredient may be incorporated in excipients or carriersconventionally used in pharmaceutical compositions such as, for example,talc, arabic gum, lactose, gelatine, magnesium stearate, corn starch,aqueous or non aqueous vehicles, polyvynil pyrrolidone, semisyntheticglicerides of fatty acids, benzalconium chloride, sodium phosphate,EDTA, polysorbate 80.

In case it is desired to further increase the solubility of thecompounds of general formula (I) or of their physiologically acceptablesalts, surfactants, non ionic surfactants such as PEG 400, cyclodextrin,metastable polymorphs, inert adsorbents such as bentonite, may beincorporated. Furthermore some techniques may be employed by preparingfor example eutectic mixtures and/or solid dispersion by using mannitol,sorbitol, saccharose, succinic acid or physical modified forms by usinghydrosoluble polymers, PVP, PEG 4000-20.000.

The compositions are advantageously formulated in dosage units, eachdosage unit being adapted to supply a single dose of the activeingredient. The dosis range applicable per day is between 0.1 to 400,preferably between 1.0 to 300, more preferably between 2 to 200 mg.

Each dosage unit may conveniently contain from 0.01 mg to 100 mg,preferably from 0.1 to 50 mg.

The dosage units are administered to the patient 1, 2, 3, or 4 timesdaily. It is preferred that the compounds of the invention beadministered either three or fewer times, more preferably once or twicedaily consecutively over a period of time.

Suitable tablets may be obtained, for example, by mixing the activesubstance(s) with known excipients, for example inert diluents such ascalcium carbonate, calcium phosphate or lactose, disintegrants such ascorn starch or alginic acid, binders such as starch or gelatine,lubricants such as magnesium stearate or talc and/or agents for delayingrelease, such as carboxymethyl cellulose, cellulose acetate phthalate,or polyvinyl acetate. The tablets may also comprise several layers.

Coated tablets may be prepared accordingly by coating cores producedanalogously to the tablets with substances normally used for tabletcoatings, for example collidone or shellac, gum arabic, talc, titaniumdioxide or sugar. To achieve delayed release or preventincompatibilities the core may also consist of a number of layers.Similarly the tablet coating may consist of a number or layers toachieve delayed release, possibly using the excipients mentioned abovefor the tablets.

Syrups or elixirs containing the active substances or combinationsthereof according to the invention may additionally contain a sweetenersuch as saccharine, cyclamate, glycerol or sugar and a flavour enhancer,e.g. a flavouring such as vanilline or orange extract. They may alsocontain suspension adjuvants or thickeners such as sodium carboxymethylcellulose, wetting agents such as, for example, condensation products offatty alcohols with ethylene oxide, or preservatives such asp-hydroxybenzoates.

Solutions for injection are prepared in the usual way, e.g. with theaddition of preservatives such as p-hydroxybenzoates, or stabiliserssuch as alkali metal salts of ethylenediamine tetraacetic acid, andtransferred into injection vials or ampoules.

Capsules containing one or more active substances or combinations ofactive substances may for example be prepared by mixing the activesubstances with inert carriers such as lactose or sorbitol and packingthem into gelatine capsules.

Suitable suppositories may be made for example by mixing with carriersprovided for this purpose, such as neutral fats or polyethyleneglycol orthe derivatives thereof.

The compounds of general formula (I) can be conveniently prepared by avariety of synthetic routes known to those skilled in the art. Accordingto a further object of the present invention, processes for thepreparation of compounds of general formula (I) are provided, in which:

-   -   a) a compound of general formula (II)

wherein R₁, R₂, R₃ and R₄ denote hydroxy or hydrogen and at least oneamong R₁, R₂, R₃ and R₄ is hydroxy, is reacted with a sulfation reagentsuch as sulfuric acid, sulfur trioxide, sulfur trioxide in the presenceof organic bases or amides or tetrabutyl ammonium hydrogensulfate incombination with dicyclohexylcarbodiimide. The synthesis of thecompounds according to formula (II) has been described in WO 01/21593A1, page 7 line 17 to page 14, line 34.

Preferred reagents are sulfur trioxide in the presence of tertiaryamines such as trimethylamine, triethylamine or pyridine, or sulfurtrioxide in the presence of dimethylformamide and combinations thereof.Particularly preferred reagent is sulfur trioxide complexed withdimethylformamide in the presence of pyridine.

The reaction can be conveniently carried out at temperature ranging from10 to 50° C. under stirring, preferably between 20 and 50° C., mostpreferably at 40° C., or

-   -   b) a compound of general formula (III)

wherein R₁, R₂, R₃ and R₄ denote protected sulfate monoester or hydrogenand at least one among R₁, R₂, R₃ and R₄ is a protected sulfatemonoester, is reacted with a cleavage reagent to restore the free acidmoiety (see: Gunnarson G T et al. Biorganic and Medicinal Chemistry, 13(2005) 1783-1789; Simpson L S, Journal of the American Chemical Society128 (2006) 1605-1610). Protecting groups for sulfates are represented byalkyl and halogenated alkyls, preferably isobutyl, neopentyl and2,2,2-trichloroethyl. In case the protecting group is alkyl, theprotected sulfates can be cleaved with nucleophiles in polar aproticsolvents. Examples of nucleophiles are azide, cyanide, iodide andthiocianate; as solvents dimethylformamide and acetone can beconveniently used. The reaction can be conveniently carried out in warmsolvents, preferably between 50 and 70° C.

Protected sulfates of general formula (III) can be conveniently preparedby reacting a compound of general formula (II), wherein R₁, R₂, R₃ andR₄ denote hydroxy or hydrogen and at least one among R₁, R₂, R₃ and R₄is hydroxy, with suitable alkylchlorosulfates or halogenatedalkylchlorosulfates in the presence of a base in an aprotic solvent.Examples of alkylchorosulfates are isobutylchlorosulfate andneopentylchlorosulfate, example of halogenated alkylchlorosulfate is2,2,2-trichloroethyl chorosulfate. As bases, organic or inorganic basescan be used: non limitative examples are: dimethylaminopyridine,triethylamine, DBU, sodium hydride, sodium bis(trimethylsilyl)amide,etc. As solvent, tetrahydrofurane can be conveniently used.

Alternatively, the compounds of the present invention can be synthesizedby enzymatic processes using S9 fractions from human or animal livers asthe source of sulfotransferases andadenosine-3′-phosphate-5′-phosphosulfate (PAPS) as the sulphate donor(Foldes A, Meek J L, Biochem. Biophys. Acta 327:365-374, 1973; Honma Wet al., drug Metabolism and Disposition 30: 944-949, 2002; Wang Q et al.In Vitro Cell. Dev. Biol.-Animal 41: 97-103, 2005). A typical incubationmixture consists of 100 mM potassium phosphate buffer (pH 7.4), 10 mMmagnesium chloride, 1 mM PAPS, human or animal (rat, dog, monkey) liverS9 fraction (commercially available) adjusted to a final proteinconcentration of 1 mg/mL and of 10-100 μM of a compound of generalformula (II) as the substrate. The reaction is initiated by the additionof PAPS and terminated by the addition of 4 times the volume of ice-coldacetonitrile after incubation at 37° C. for 2 to 8 hours depending onthe substrate molecule. The mixture is centrifuged to sediment theprecipitated protein. The supernatant containing the compound sulphateis concentrated under a stream of nitrogen, re-suspended in water andpurified by liquid chromatography using a C18 separating column (100×4.6mm ID, ProC18, YMC, Schermbeck, Germany) protected by a guard column(15×4 mm ID, Purosphere E, C18, Merck, Germany) and a flow rate of 1mL/min. A linear gradient (mobile phase A: 0.1% HCOOH and 10% ACN inwater, mobile phase B: 0.1% HCOOH and 75% ACN in water) where ACNconcentration increases from 10 to 75% within 25 minutes can be used toseparate the sulphate from impurities. The identity of the purifiedsulphate can be verified by HPLC (mobile phase: 0.1% ammonium formiate,pH 3.3 and 70% acetonitrile in water, 0.3 mL/min flow rate) interfacedto an electrospray (positive) ionization tandem mass spectrometry (API365, Perkin-Elmer-Sciex, Canada) using a pneumatically assistedelectrospray ionisation source. The structure is verified byfragmentation of the [M+H]+ ion (m/z 583). The consecutive loss of 2 SO3moieties (−80 amu, respectively) leads to the key fragment C (m/z 423).At higher collision energies fragment m/z 177 (hydroxylatedbenzimidazolone structure) is also observed.

As mentioned before, the compounds of formula (I) according to thepresent invention, surprisingly show interesting pharmacologicalproperties owing to their different profile at the serotonine ordopamine receptor subtypes, such as 5-HT_(1A) and 5-HT_(2A). Thebiochemical profile of the compounds was assessed by evaluating theiraffinity for the 5-HT_(1A) and 5-HT_(2A) receptors, according to themethods described below.

Receptor Binding Studies

Binding studies can be carried out to determine the affinity of thecompounds for 5-HT_(1A) and 5-HT_(2A) receptors

5-HT_(1A) Receptor

Human recombinant CHO-K1 cells are used. Displacement experiments can beperformed by incubating the cells in 50 mM Tris-HCL, pH 7.4, 0.1%ascorbic acid, 0.5 mM EDTA, 10 mM MgSo4 and in the presence of[³H]-8-OH-DPAT (1.5 nM) at 27° C. for 60 min. Non specific binding wasdetermined in the presence of 10 μM mertergoline.

The test compounds dissolved in DMSO, along with the positive controlcompound metergoline are tested over 10-log unit concentrations fortheir ability to compete for [³H]8-OH-DPAT binding (May J A, et al., JPharmacol Exp Ther. 306(1):301, 2003. Martin G R and Humphrey P P ANeuropharmacol. 33:261, 1994). The assays are terminated by rapid vacuumfiltration over glass fiber filters. The radioactivity is counted on aβ-counter, and the data are analyzed by a nonlinear, iterative,curve-fitting computer program.

Where presented, IC50 values are determined by a non-linear, leastsquares regression analysis using Data Analysis Toolboxä (MDLInformation Systems, San Leandro, Calif., USA). Where inhibitionconstants (Ki) are presented, the Ki values are calculated using theequation of Cheng and Prusoff (Cheng, Y., Prusoff, W. H., Biochem.Pharmacol. 22:3099-3108, 1973) using the observed IC50 of the testedcompound, the concentration of radioligand employed in the assay, andthe historical values for the Ki of the ligand).

5 HT_(2A) Receptor

Human recombinant CHO-K1 cells can be used. Displacement experiments areperformed by incubating the cells in 50 mM Tris-HCL, pH 7.7 in thepresence of [³H]-Ketanserin (0.5 nM) at 25° C. for 60 min. Non specificbinding was determined in the presence of 1 μM Mianserin.

The test compounds, along with the positive control compound ketanserinare tested over 10-log unit concentrations for their ability to competefor [³H]-Ketanserin (Saucier C and Albert P R. J Neurochem. 68:1998,1997. Bonhaus D W et al., Br J Pharmacol. 115:622, 1995). The assays areterminated by rapid vacuum filtration over glass fiber filters. Theradioactivity is counted on a β-counter, and the data are analyzed by anonlinear, iterative, curve-fitting computer program. Where presented,IC50 values are determined by a non-linear, least squares regressionanalysis using Data Analysis Toolboxä (MDL Information Systems, SanLeandro, Calif., USA). Where inhibition constants (Ki) are presented,the Ki values are calculated using the equation of Cheng and Prusoff(Cheng, Y., Prusoff, W. H., Biochem. Pharmacol. 22:3099-3108, 1973)using the observed IC50 of the tested compound, the concentration ofradioligand employed in the assay, and the historical values for the Kiof the ligand).

The following table (Table I) collects the affinity values (Ki, nM) atthe said receptors of the new compounds.

TABLE I Ki (nM) for 5-HT_(1A) and 5-HT_(2A) receptors Compound 5-HT_(1A)5-HT_(2A) I(b) 808 207

EXPERIMENTAL PART

The following examples illustrate the preparation of compounds accordingto the invention. It should be understood that the invention is notlimited to the given examples of chemical methods and processes for thepreparation of the substances, as other conventional methods well knownto those skilled in the art, are suitable too.

Example 1{2-oxo-3-{2-[4-(3-trifluoromethyl-phenyl)-piperazin-1-yl]-ethyl}-2,3-dihydro-1H-benzimidazol-5-yl}monosulfuric acid ester

6-Hydroxy-1-{2-[4-(3-trifluoromethyl-phenyl)-piperazin-1-yl]-ethyl}-1,3-dihydro-benzimidazol-2-one(2.0 g; 4.9 mmol) is dissolved in pyridine (10 ml) in a round bottomflask under stirring. Sulfur trioxide dimethylformamide complex (3.8 g,24.2 mmol) dissolved in pyridine (4 ml) is added at room temperature;then the mixture is warmed to 40° C. until a suspension is formed.

The reaction mixture is evaporated under vacuum to remove most of theliquid. The almost solid residue is taken up in 1:1 mixture ofethylether and ethylacetate, then triturated and filtered throughfritted glass. The residual solid is repeatedly washed with water andfinally with ethyl ether. Upon drying, the title compound is obtained assolid, 1.48 g;

-   -   m.p. 262-264° C.

The other sulfates can be prepared by the outlined procedure from thecorresponding hydroxy derivatives described in WO 01/21593 A1 on page 2line 13 to 29. Those hydroxy derivatives can be synthesized as describedin WO 01/21593 A1, page 7 line 17 to page 14, line 34.

Example 25-Methoxy-1-{2-[4-(4-methoxy-3-trifluoromethyl-phenyl)piperazin-1-yl]-ethyl}-1,3-dihydro-benzimidazol-2-onei)N-(4-Methoxy-2-nitro-phenyl)-2-[4-(4-methoxy-3-trifluoromethyl-phenyl)-piperazin-1-yl]acetamide

2-Bromo-N-(4-methoxy-2-nitro-phenyl)-acetamide (6.7 g; 19.6 mmol) isdissolved in 200 ml ethanol in the presence of 6.3 g sodium carbonate.1-(4-Methoxy-3-trifluoromethyl-phenyl)-piperazine hydrochloride (5.8 g;19.6 mmol) is added to the resulting suspension and the mixture isstirred overnight at room temperature. The mixture is evaporated todryness under vacuum and the residue is taken up with water andethylacetate. The organic phase is separated and washed twice withwater. After drying over magnesium sulfate, evaporation of the solventleaves a residue which is triturated with ethylether.

ii)2-Amino-4-methoxy-N-{2-[4-(4-methoxy-3-trifluoromethyl-phenyl)piperazin-1-yl]-ethyl}-aniline

N-(4-Methoxy-2-nitro-phenyl)-2-[4-(4-methoxy-3-trifluoromethyl-phenyl)-piperazin-1-yl]acetamide(6.1 g; 11 mmol) is dissolved in 70 ml tetrahydrofurane.Borane-tetrahydrofurane complex (90 ml of 1M THF solution) is added at10° C. and the mixture is warmed to 55° C. for 4 hours. After cooling toroom temperature, the solvent is evaporated under vacuum and the residueis taken with ethanol and acidified with hydrochloric acid. Heating to50° C. takes place for 60 min. Upon overnight cooling, the unreactedcompound is separated by filtration. The liquid phase is dried undervacuum, taken up with water and, after removal of the undissolved solid,saturated sodium hydrogencarbonate solution is added. The aqueous phaseis extracted with ethylacetate and the organic layer is dessicated priorto evaporation. The residue is purified by silicagel chromatography(methylene chloride/methanol/32% aqueous ammonia 95:5:0.5). The titlecompound can be directly used for the following step.

iii)5-Methoxy-1-{2-[4-(4-methoxy-3-trifluoromethyl-phenyl)piperazin-1-yl]-ethyl}-1,3-dihydro-benzimidazol-2-one

2-Amino-4-methoxy-N-{2-[4-(4-methoxy-3-trifluoromethyl-phenyl)piperazin-1-yl]-ethyl}-aniline(2.5 g, 6 mmol) is dissolved in 30 ml tetrahydrofurane; 1.5 g (9 mmol)carbonyldiimidazole is added portionwise to the resulting solution. Themixture is left at room temperature under stirring for 24 h. Afterevaporation to dryness, the residue is purified by silicagelchromatography (methylene chloride/methanol/32% aqueous ammonia95:5:0.5). The crude title compound is triturated with ethylether.

Example 31-{2-[4-(2-Methoxy-5-trifluoromethyl-phenyl)-piperazin-1-yl]-ethyl}-1,3-dihydro-benzimidazol-2-one

1-(2-methoxy-5-trifluoromethyl-phenyl)-piperazine hydrochloride (1.2 g;4.0 mmol) and 1-(2-chloroethyl)-1,3-dihydro-benzimidazol-2-one (0.81 g;4.2 mmol) are dissolved in 10 ml dimethylformamide in the presence of0.56 g potassium carbonate. The mixture is heated to 100° C. for 8hours. After cooling, it is partitioned between 50 ml water and 30 mlethylacetate; the aqueous phase is extracted once more withethylacetate. The organic layer is washed with 5% hydrochloric acid andwith water. The organic layer is dried and evaporated under vacuum. Theresidue is triturated with ethylacetate.

The deprotection of the hydroxy groups of the compounds described inExample 2) and 3) can easily carried out by conventional knownprocedures e.g. as described in WO 01/21593 A1. For example, thedeprotection can be achieved by treatment with strong aqueous acids suchas 48% hydrobromic acid at high temperatures or alternatively bytreatment with boron derivatives such as BBr₃, at low temperatures inchlorinated solvents such as methylene chloride. The resultingdeprotected hydroxy-derivatives can be easily converted to thecorresponding disulfate ester as described in Example 1.

Examples of Pharmaceutical Formulations

A) Tablets per tablet compound (I.a) 100 mg lactose 240 mg corn starch340 mg polyvinylpyrrolidone  45 mg magnesium stearate  15 mg 740 mg

The finely ground active substance, lactose and some of the corn starchare mixed together. The mixture is screened, then moistened with asolution of polyvinylpyrrolidone in water, kneaded, wet-granulated anddried. The granules, the remaining corn starch and the magnesiumstearate are screened and mixed together. The mixture is compressed toproduce tablets of suitable shape and size.

B) Tablets per tablet compound (I.b) 80 mg corn starch 190 mg  lactose55 mg microcrystalline cellulose 35 mg polyvinylpyrrolidone 15 mgsodium-carboxymethyl starch 23 mg magnesium stearate  2 mg 400 mg 

The finely ground active substance, some of the corn starch, lactose,microcrystalline cellulose and polyvinylpyrrolidone are mixed together,the mixture is screened and worked with the remaining corn starch andwater to form a granulate which is dried and screened. Thesodium-carboxymethyl starch and the magnesium stearate are added andmixed in and the mixture is compressed to form tablets of a suitablesize.

C) Coated tablets per coated tablet compound (I.c)  5 mg corn starch41.5 mg   lactose 30 mg polyvinylpyrrolidone  3 mg magnesium stearate0.5 mg  80 mg

The active substance, corn starch, lactose and polyvinylpyrrolidone arethoroughly mixed and moistened with water. The moist mass is pushedthrough a screen with a 1 mm mesh size, dried at about 45° C. and thegranules are then passed through the same screen. After the magnesiumstearate has been mixed in, convex tablet cores with a diameter of 6 mmare compressed in a tablet-making machine. The tablet cores thusproduced are coated in known manner with a covering consistingessentially of sugar and talc. The finished coated tablets are polishedwith wax.

D) Capsules per capsule compound (I.d)  1 50 mg Corn starch 268.5 mgMagnesium stearate  1.5 mg   420 mg

The substance and corn starch are mixed and moistened with water. Themoist mass is screened and dried. The dry granules are screened andmixed with magnesium stearate. The finished mixture is packed into size1 hard gelatine capsules.

E) Ampoule solution compound (I.e) 50 mg sodium chloride 50 mg water forinj.  5 ml

The active substance is dissolved in water at its own pH or optionallyat pH 5.5 to 6.5 and sodium chloride is added to make it isotonic. Thesolution obtained is filtered free from pyrogens and the filtrate istransferred under aseptic conditions into ampoules which are thensterilised and sealed by fusion.

F) Suppositories compound (I.f)  50 mg solid fat 1650 mg 1700 mg

The hard fat is melted. At 40° C. the ground active substance ishomogeneously dispersed. It is cooled to 38° C. and poured into slightlychilled suppository moulds.

1. Compounds of general formula (I)

wherein R₁, R₂, R₃, and R₄ denote hydrogen or sulfate monoester with theproviso that R₁, R₂, R₃, and R₄ cannot simultaneously representhydrogen, or a pharmacologically acceptable salt thereof.
 2. Compoundsof general formula (I) according to claim 1 wherein two or three of thefour radicals R₁, R₂, R₃, and R₄ denote hydrogen.
 3. Compound accordingto claim 1 or 2, selected form the group consisting of

or a pharmacalogically acceptable salt thereof.
 4. Process for thepreparation of compounds of general formula (I) according to one or moreof claims 1 to 3, characterized in that a compound of general formula(II)

wherein R₁, R₂, R₃ and R₄ denote hydroxy or hydrogen and at least oneamong R₁, R₂, R₃ and R₄ is hydroxy, is reacted with a sulfation reagent.5. Process for the preparation of compounds of general formula (I)according to one or more of claims 1 to 3, characterized in that acompound of general formula (III),

wherein R₁, R₂, R₃ and R₄ denote protected sulfate monoester or hydrogenand at least one among R₁, R₂, R₃ and R₄ is a protected sulfatemonoester, is reacted with a cleavage reagent to restore the free acidmoiety.
 6. Compound of formula (I) according to one or more of claims 1to 3 for use as a medicament.
 7. Pharmaceutical compositions comprisingas an active ingredient a compound of formula (I) according to one ormore of claims 1 to 3 in admixture with one or more pharmaceuticalcarriers, diluents or excipients.
 8. Use of a compound of formula (I)according to one or more of claims 1 to 3, optionally in form of thepharmacologically acceptable salts thereof for preparing a medicamentfor preventing and/or treating diseases in which the use of therapeuticeffective amounts of compounds displaying affinity for the 5-HT_(1A) and5-HT₂-receptor may have a therapeutic benefit.
 9. Use of a compound offormula (I) according to one or more of claims 1 to 3, optionally inform of the pharmacologically acceptable salts thereof for preparing amedicament for preventing and/or treating sexual disorders.
 10. Useaccording to claim 9 wherein the sexual disorder is selected from thegroup consisting of Sexual Desire Disorders, Sexual Arousal Disorders,Orgasmic Disorders, Sexual Pain Disorders, Sexual Dysfunction due to aGeneral Medical Condition, Substance-Induced Sexual Dysfunction, andSexual Dysfunction not otherwise specified.
 11. Use according to claim10 wherein the Sexual Desire Disorder is Hypoactive Sexual DesireDisorder.
 12. Use of a compound of formula (I) according to one or moreof claims 1 to 3, optionally in form of the pharmacologically acceptablesalts thereof for preparing a medicament for preventing and/or treatingpremenstrual disorders.